Explanation: This pretty,
open cluster of stars,
M34, is about the size of
the Full Moon on the sky.
Easy to appreciate in small telescopes,
it lies some 1,800 light-years away in the constellation
Perseus.
At that distance, M34 physically spans about 15 light-years.
Formed at the same time from the same cloud of dust and gas,
all the stars of M34
are about 200 million years young.
But like
any open star cluster orbiting in the
plane of
our galaxy, M34 will eventually disperse as it experiences
gravitational tides and encounters with the
Milky Way's
interstellar clouds and other stars.
Over four billion years ago, our own Sun was likely
formed in a similar
open star cluster.